Mould in the home is common, but it shouldn’t be ignored.

Left untreated, mould can spread, damage surfaces, affect indoor air quality and signal an underlying moisture problem. While many people focus on removing the visible mould, the real challenge is identifying why it appeared in the first place.

This guide explains:

  • What mould is
  • Why identifying it matters
  • When DIY cleaning may be appropriate
  • When professional help is the safer option
  • Practical steps to help prevent mould returning


What is mould

Mould is a type of fungus that grows where moisture, warmth and limited airflow exist. It is not necessarily a sign of poor cleaning!

Bathrooms, laundries, kitchens and areas affected by leaks or water damage are common problem zones.

If the moisture problem isn't addressed, mould will usually return regardless of which cleaning product is used.

 

There are many types of mould

Homes can host many different types of mould. Some grow on hard surfaces in humid areas, while others can establish themselves inside walls, ceilings, carpets, insulation, timber and other porous materials.

This distinction is important because the safest approach depends on:

  • The size of the affected area
  • The type of surface involved
  • Whether the mould is superficial or established
  • Whether the mould continues to return

A small patch on bathroom tiles is very different from mould growing behind a wall after a plumbing leak.

For a detailed breakdown of common mould types and where they are typically found, see: Mold Types Found in Homes – Mold Advisor

 

When DIY mould cleaning may be appropriate

Small amounts of surface mould on non-porous surfaces can often be cleaned safely.

Examples include:

  • Bathroom tiles
  • Shower screens
  • Glass
  • Sealed hard surfaces

If you choose to clean a small affected area yourself:

  • Wear gloves and appropriate personal protection
  • Ensure good ventilation
  • Avoid dry brushing mould
  • Dry the area thoroughly afterwards
  • Address the source of moisture

Some people choose to use:

  • Hydrogen peroxide
  • Sodium percarbonate solutions

These can help clean the surface and remove visible mould staining. However, no cleaning product can compensate for ongoing moisture problems. If the area remains damp, mould is likely to return.

When DIY cleaning is not recommended

    Professional assessment is usually the safer option when:

    • Mould covers a large area
    • Mould keeps returning after cleaning
    • Walls or ceilings are affected
    • Carpet, insulation, plasterboard or timber are involved
    • There is a persistent musty smell
    • The home has experienced flooding or water damage
    • Anyone in the household has respiratory sensitivities or health concerns

    In these situations, the mould you can see may only be part of the problem.

    Who should you contact?

    If mould is widespread, recurring or linked to water damage, consider contacting:

    • A qualified mould remediation specialist
    • A water damage restoration company
    • A building inspector experienced in moisture issues
    • A plumber if an active leak is suspected

    A professional assessment can help identify the source of moisture and determine the most appropriate remediation strategy.

     

    Commercial mould killers

    Many commercial mould and mildew products rely on chlorine-based ingredients such as sodium hypochlorite.

    These products can be effective at whitening stains and removing visible mould, but they also produce strong fumes and can irritate the eyes, skin and respiratory system.

    They should always be used according to the manufacturer's directions with appropriate ventilation.

    Never mix chlorine-based products with other cleaning chemicals, as dangerous gases can be produced.

     

    Prevention is always the best approach

    The most effective way to manage mould is to remove the conditions it needs to survive.

    Focus on:

    • Ventilating bathrooms and laundries
    • Using exhaust fans where available
    • Drying wet surfaces after use
    • Fixing leaks promptly
    • Reducing indoor humidity
    • Allowing airflow into cupboards and enclosed spaces
    • Cleaning and maintaining areas prone to condensation

    A dry surface is an inhospitable surface for mould.

     

    The key takeaway

    Cleaning visible mould is only part of the solution. The real goal is identifying and addressing the moisture source that allowed it to grow in the first place.

    For small areas of surface mould, careful cleaning and improved moisture control may be enough. For larger, recurring or hidden mould problems, professional advice is often the safest and most effective path forward.

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